KEY STEPS

Compendium on methods and tools to evaluate impacts of, and vulnerability and adaptation to, climate
change

Environmental Burden of Disease Assessment

Description

The global burden of disease attributable to climate change was recently estimated as part of a
comprehensive World Health Organization (WHO) project. The project sought to use standardized
methods to quantify disease burdens attributable to 26 environmental, occupational, behavioral, and
life-style risk factors in 2000 and at selected future times up to 2030.

The Environmental Burden of Disease (EBD) tools include guidelines on how to estimate the
approximate magnitude of the health impacts of various environmental factors, including climate
change, at the national or regional level, to help determine priorities for action.

Appropriate Use

An EBD assessment for climate change will indicate which impacts could be greatest and in which
regions, and how much of the climate-attributable disease burden could be avoided by emissions
reduction. It also will guide health-protective strategies.

Scope

An EBD assessment is usually conducted on a national or regional scale.

Key Output

Comparative risk assessment attempts to answer the following questions:

How much disease is caused by climate change (attributable burden of disease)?

How much could be avoided by making plausible reductions in the exposure (avoidable burden of
disease)?

The outputs can be defined by the user, but are usually in DALYs (disability adjusted life years)
or avoided deaths that can be compared between populations and between specific health impacts of
climate change.

Key Input

The following are needed to determine the amount of climate-sensitive disease that is attributable
to climate change:

the baseline burden of climate-sensitive diseases;

The estimated increase in the risk of disease/disability per unit increase in exposure to
climate change;

The current or estimated future population distribution of exposure.

The avoidable burden of climate-sensitive diseases is estimated by comparing projected burdens
under alternative exposure scenarios. The global assessment used WHO estimates of the baseline
burden of cardiovascular deaths associated with thermal extremes, diarrhea episodes, cases of
malaria, malnutrition, and deaths due to natural disasters.

Examples of global and regional assessments previously published by the WHO and Australian National
University. Guidelines for comparative risk assessment methods have been published by WHO, with
guidelines for national and regional assessments forthcoming in early 2004.